Incubators for infants



Dec. 12, 1961 w. H. SMITH EFAL 3, ,8

INCUBATORS FOR INFANTS Original Filed April 23, 1957 4 Sheets-Sheet 1 FIG. I.

I 56 l 54- 7 8 B2 122 I 129 135 INVENTORS WILLIAM HAROLD SMITH 2, RUDOLPH FROHNER AND ROY T. ADOLPHSON BY ATTORN EY Dec. '12, 1961 w. H. SMITH ETAL 3,012,836

INCUBATORS FOR INFANTS Original Filed April 23, 1957 4 Sheets-Sheet 2 INVENTORS WILLIAM HAROLD SMITH RUDOLPH FROHNER AND ROY T. ADOLPHSON ATTORNE Dec. 12, 1961 w. SMITH ETAL INCUBATORS FOR INFANTS Original Filed April 23, 1957 4 Sheets-Sheet 3 INVENTORS WILLIAM HAROLD SMITH RUDOLPH FROHNER AND ROY T ADOLPH SON ATTORNEY Dec. 12, 1961 w. H. SMITH ETAL INCUBATORS FOR mums D H W N 4 mMmo 5N5 t T H e e N L O P h E O R L S R F 0 r V A D t N H e IMP. 6 LT h O S L Y H O W R R Original Filed April 23, 1957 ATTORNEY United States Patent Ofiice 3,912,836 Patented Dec. 12, 1961 3 Claims. (Cl. 312296) This invention relates in general to certain new and useful improvements in incubators for infants and, more particularly, to an incubator which is particularly adapted for the care and nurturing of prematurely born infants. This application is a division of our co-pending application, Serial No. 654,503, filed April 23, 1957.

It has become a well-established obstetric and pediatric practice to place prematurely born infants in an incubator designed to enclose the infant within an atmosphere having precisely controlled conditions of temperature, humidity, and, when necessary, the proper degree of oxygen enrichment.

Particularly in view of recent medical research with respect to the effect of an oxygen-rich atmosphere upon eye tissue, it has become increasingly important to employ an incubator in which the oxygen-carbon dioxide balance and humidity within the incubator can be very precisely adjusted and controlled. In the case of premature infants, it is also occasionally necessary to deal, on an emergency basis, with such conditions as anaphylactic shock, pulmonary congestion, and similar conditions which require a so-called Trendelenberg position, that is to say, a position in which the infants body can be inclined with the head and shoulders at a lower level than the feet and hips. Not only is it desirable to place the infant in a so-called Trendelenberg position, but it is also equally desirable that varying degrees of Trendelenberg inclination are available up to an angle of approximately 15.

A further problem which has been encountered in infant incubators of present design relates to the physical handling of the infant. Many existing types of infant incubators are of box-like shape having hinged top-lids or hinged doors in a side wall. Such lids and doors are usually quite heavy and may accidentally drop down as the infant is being removed from or placed into the incubator. It is possible that the door, in accidentally dropping, may strike and injure the infant, or, as is more likely, strike and bruise the forearms of the nurse handling the infant. Closely related to this problem is the further problem of complete visibility. When a medical emergency occurs in the life of a premature infant, very often a matter of a few seconds in taking action can mean the difference between life and death. For this reason, it is considered highly essential that infant incubators afford a View of the infant which is as clear and unobstructed as possible while, at the same time, affording extremely quick and convenient physical accessibility to the infant.

Similarly, infant incubators must, of necessity, contain a variety of mechanical and electrical components which can fail during periods of use, no matter how carefully constructed and efiiciently maintained. With existing and available types of incubators, the only thing which can be done when such mechanical failure occurs is to transfer the infant from the inoperative incubator to an incubator which is in working order. This, however, entails a certain amount of hazard, because premature infants are usually very delicate and sensitive for a number of weeks after birth and are highly susceptible to drafts, airborne infections and similar ills which can result from even a short period of exposure while being transferred from one incubator to another.

It is, therefore, one of the primary objects of the present invention to provide an infant incubator in which the conditions of temperature, pressure, and humidity'can be precisely controlled.

It is another primary object of the present invention to provide an infant incubator in which the oxygen-concentration and oxygen-carbon dioxide balance can be precisely controlled and maintained.

It is another principal object of the present invention to provide an infant incubator which affords a clear and substantially unobstructed view of the infant from all sides, regardless of whether the incubator is closed or open, and also provides quick, simple, and convenient physical access to the infant.

It is a further object of the present invention to provide an infant incubator having hand ports and closures therefor which are substantially leak-proof and, at the same time, interpose virtually no interference With clear vision into the interior of the incubator.

It is also an object of the present invention to provide an infant incubator having hand ports of the type stated which will open under the slightest degree of physical pressure as the hand is inserted into the incubator and will automatically close in a substantially leak-proof manner as the hand is withdrawn.

It is an additional object of the present invention to provide an infant incubator which can be quickly and easily opened for inserting and removing the infant and for access to the infant in times of emergency.

It is likewise an object of the present invention to provide an incubator in which the infant can be easily, quickly, and conveniently disposed in a Trendelenberg position.

It is also an object of the presentinvention to provide an infant incubator having unique and novel means for filling and draining the water reservoir associated with the humidifying apparatus.

It is also an important object of the present invention to provide an infant incubator in which all of the mechan ical and electrical components can be quickly removed or installed as a unit without disturbing the infant housed within the interior of the incubator.

With the above and other objects in view, our invention resides in the novel features of form, construction, arrangement, and combination of parts presently described and pointed out in the claims.

In the accompanying drawings- FIG. 1 is a perspective view of an infant incubator constructed in accordance with and embodying the present invention;

FIG. 2 is a front elevational view of the infant incubator;

FIGS. 3 and 4 are, respectively, end elevational views of the opposite transverse ends of the infant incubator;

- FIG. 5 is a perspective view of the infant incubator in fully opened position;

- FIG. 6 is a vertical sectional view taken along line 6-6 of FIG. 2;

FIG. 7 is a fragmentary sectional view taken along line 7-7 of FIG. 6; and

FIG. 8 is an exploded view of the closure element forming a part of the present invention.

Referring now in more detail and by reference characters to the drawings, which illustrate practical embodiments of the present invention, A designates an infant incubator comprising a box-like rectilinear base housing 1 having a vertical rear wall 2, side walls 3, 4, horizontal top and bottom Walls 5, 6, and a pair of relatively narrow front wall panels 7, S, the inner vertical margins of which, in conjunction with the forward margins of the top and bottom walls 5, 6, form a forwardly presented rectangular drawer-opening 9.

The top wall 5 is provided along its longitudinal axis with two symmetrically arranged, somewhat oblong depressions 10, 11, having bottom walls 12, 13, respectively, which are, in turn, provided with air circulation apertures 14, 15.

Rigidly mounted around its lower peripheral margins upon the base housing 1 and extending upwardly over the rear half of the top wall 5 is a rear or stationary shelllike halfdome 16 formed of clear acrylic resin, Lucite, or other similar transparent material, and being provided around its forwardly presented vertical and horizontal margins with a narrow upturned flange 17. The halfdome 16 integrally includes vertical side walls 18, 19, and a back wall 20, the lower portion of which is substantially vertical and the upper portion of which is substantially quatri cylindrical. The bank wall 20 of the halfdome 16 is provided with two circular apertures 21, 22, of sufficiently large diametral size to freely and loosely admit the passage of the hand, wrist, and forearm, of a nurse, doctor, or other adult attendant.

Provided for disposition across each of the apertures 21, 22, are flexible, transparent, glass-like closure elements 23, each comprising a mounting bar 24 formed preferably of clear Lucite or other similar synthetic plastic material and having a fiat face 25 for snug-fitting disposition against the interior face of the halfdome 16, being adapted for securement thereto by means of small screws 26 which are threaded into internally threaded recesses 27. The mounting bar 24 is also provided on its flat face 25 with a pair of parallel recesses 28, which open upon the fiat face 25 and also extend outwardly into the arcuate back face of the mounting bar 24 for snugly accommodating and retentively engaging the opposite ends of a U-shaped tightly-wound spiral spring 29, which is disposed within, and extends around the peripheral margins of, a flap-forming fiat envelope 30 comprising two facewise overlying marginally bonded sheets 31, 32, of transparent Pliolilm or other similar material. When the plastic encased upper ends of the spring 29 are seated Within the recesses 28, the intervening upper marginal portion of the flap-forming envelope 30 will be in snugfitting fiat abutment across the flat face 25 of the bar 24 and is provided with apertures 33, for registration with the apertures 27. Thus, when the screws 26 are drawn up tightly, the bar 24 will hold the fiat-forming envelope 30, together with the spring 29 encased therein, and, in turn, the spring 29 will be slightly flex, as shown in FIG. 6, thereby holding the flap-forming envelope 30 in snug-fitting substantially leak-proof closure-forming position against the interior surfaces of the halfdome 16. The closure members 23 are extremely light in weight and can be readily pushed aside to admit the hand or arm of the attendant for purposes of administering to the needs of the infant in the incubator. However, the closure members 23 will immediately and eflectively return to closure-forming position as soon as the hand or arm is withdrawn, thereby preventing any air leakage into or out of the incubator. 1

Also rigidly mounted in and extending through the side wall 18 of the halfdome 16 is a suitably bent piece of piping or tubing 34, which can be closed from the outside in any conventional manner, as, for instance, by means of a suitable cap or cork (the latter not being shown). The tubing 34 is actually not an essential part of the incubator, but is shown and optionallyprovided to permit the use of nebulizers and other therapeutic equipment which some doctors, upon occasion, use in handling certain types of incubator cases. These various types of nebulizers and related therapeutic devices form no part of the present invention and are, therefore, not shown or described herein.

At the approximate geometric center of the are forming the top portion of the back wall 20, the side walls 18, 19, are provided with pivots 35, 36, respectively, for rockably supporting a companion-shaped halfdome 37 formed of transparent Lucite or similar material and being substantially similar in shape to the stationary halfdome 16, in-

tegrally including vertical side walls 38, 39, and a front wall 40. Around its rearwardly presented U-shaped peripheral lid, the halfdome 37 is provided with a flexible bead 41 formedpreferably of neoprene or other oxygenresistant rubber-like material and integrally including a rearwardly and upwardly presented flexible flange 42, which is in edgewise seated wiping contact with the inner faces of the rear halfdome 16. Consequently, when the front halfdome 37 is down in the closed position shown in FIG. 1. the interior of the incubator above the base housing 1 will be enclosed in a substantially leak-proof completely transparent dome. However, when desired, the front halfdome 37 can be swung upwardly to the position shown in FIG. 5 to afford complete access to the interior of the incubator. To facilitate the upward swinging movement of the halfdome 37, it is provided with a suitable handle 43. Furthermore, to provide convenient manipulative access to the interior of the incubator, the forward halfdome 37 is provided with two circular apertures 44, 45, which are substantially identical in shape and location to the apertures 21, 22, and are fitted with closure elements 23 in the same manner as the corresponding apertures 21, 22.

Along one transverse margin the top wall 5 is provided with two short upwardly projecting round-topped pins 46, 47, which are located symmetrically on opposite sides of the longitudinal center line of the top wall 5 in frontto-Iear alignment, substantially as shown in FIGS. 6 and 7. Similarly, the bottom wall 13 of the recess 11 is provided with an aperture 48 and a grommet plate 49 for slidably accommodating a vertical rod 59, which extends downwardly therethrough and is bent at its lower end in the provision of a. horizontal leg 51, which projects through, and is held rigidly in, a slide-fitting 52 operatively mounted in a slot 53 formed in the side wall 4 of the base housing 1. Externally of the side wall 4, the slide-fitting 52 is provided with a somewhat loose clamp ing plate 54 which can be shifted inwardly into tight clampwise abutment against the outwardly presented face of a reinforcing plate 55 which is riveted upon the outer face of the side wall 4 in marginal registration with the slot 53. The outwardly projecting end of the horizontal leg 51is threaded for operatively supporting a knurled knob 56 having an inwardly presented flat face 57 which bears against the plate 54 and forces it into clamping position when desired. Inwardly of the slide-fitting 52, the horizontal leg 51 of the rod 50 is provided with a freely rotating nylon collar 58 which functions somewhat in the manner of a pulley and bears against a steel ribbon 59 which is similarly trained around pulleys 60, 61, and, at

its opposite ends, is hooked into angular-1y disposed tension springs 62, 63, which are, in turn, booked at their lower ends to post-like spring retention fittings 64, 65, rigidly mounted in the bottom wall 6. Thestrength of the springs 62, 63, is such that the rod 50 will be normally biased upwardly with a force of approximately 15 to 20 lbs., so that the rod 50 and its related structure can be manually pushed downwardly to the lower limit of its travel in the slot 53 with a relatively small amount of manual force and can be locked in any position of vertical adjustment within the slot 53 by a simple manipulation of the knob 56.

At its upper end, the rod 50 is rigidly provided with a bar-shaped cross-member 66 which is more or less parallel to the transverse edges of the top wall 5 and bears upon the under face of a flat shallow pan-like tray 67 which is provided with four narrow upturned marginal flanges 68, 69, 70, 71, for retentive engagement with the peripheral edges of a mattress or pad 72, upon which the infant may rest. Inwardly from the flange 68, the tray 67 is provided with two suitably spaced apertures 73, 74, for removable disposition upon the pins 46, 47. The tray 67 can, therefore, be lifted upwardly and outwardly for removal from the incubator and can be readily replaced in a similar manner. When desired, the rod 50 can be elevated to any desired position between the limits of its travel within the slot 53 and the tray 67 thereby shifted into any desired angular position, as shownin FIG. 7. As shown in the drawings, the tray can be elevated from the horizontal position to an extreme angular position of approximately 16", such extreme position being sufficient for all recognized pediatric purposes, but it will, of course, be understood that an even greater angle of inclination can be obtained by varying the dimensions of the abovedescribed structural elements.

Rigidly secured to the rear wall 2 by means of bolts 75 are U-shaped slide-channels 76, which extend horizontally forwardly and, at their forward ends, are secured by means of bolts 77 to inturned vertical flanges 78 formed integrally with the front wall 8 and facing laterally upon the opening 9 in the base housing 1. Provided for slidable disposition upon the channels 76 is a drawer-like rectangular pan 79 which extends transversely across the interior of the base housing 1 between the channels 76 and beneath the openings 14, 15, in the top wall thereof. The pan 79 is transversely divided approximately midway of its length by a short upstanding partition wall 80, which does not extend to the full height of the pan 79 and, therefore, permits the flow of air and vapor from one end to the other of the pan 79, but, nevertheless, divides the pan into two substantially separate compartments a, b. The pan 79 is finally provided around its entire peripheral margin with a flat rectangular flange 81, which supports a continuous gasket 82 and a closure-forming lid 83, which is tightly secured by bolts 84. The lid 83 is, furthermore, provided at its opposite ends with two apertures 85, 86, which are in vertical alignment with, and lie directly beneath, the apertures 14, 15, respectively, and cemented or otherwise suitably secured upon the top face of the lid 83 in concentric rela tion around the apertures 85, 86, are sealing gaskets 87, 88, respectively, which serve to seal the space between the apertures 14, 85, and 15, 86, so that the air drawn out of the interior of the incubator beneath the plastic halfdomes 16, 37, through the openings 15, 86, will pass directly into the pan 79 and will, in turn, be returned thereto through the openings 14, 85, back into the interior of the incubator without leakage to the interior of the base housing 1. The pan 79 is held in tightly gasketed position beneath the top wall 5 by means of thumb screws 89, 90, which extend downwardly through suitable apertures formed in the bottom walls 12, 13, of the recesses 10, 11, and are threadedly engaged in nuts 91, 92, respectively, which are welded, soldered, or otherwise rigidly attached to the under faces of lateral portions of the pan flange 81. The bottom wall 93 of the pan 79 is provided with an aperture 94 opening into compartment b and communicating with this aperture is an oxygen control valve 95 which is rigidly mounted in any conventional manner upon the under side of the bottom wall 93. This oxygen control valve 95 is substantially shown and described in United States Patent No. 2,687,741, and is, therefore, not specifically described in detail herein.

Also bolted or otherwise conventionally mounted upon, and depending from, the bottom wall 93 of the pan 79, is an electric motor 96, a drive shaft 97 which projects vertically upwardly through a suitable clearance aperture 98 in the bottom wall 93 and is, at its upper end, operatively provided with a squirrel-cage type vaned rotor or impeller 99. The motor shaft 97 is positioned so as to be substantially concentric with the openings 15, 86, and draws air axially downwardly through a flanged opening 100 formed in a small rectangular bafile-wall -1 seated across the top portion of the compartment b between the upper rim of the blower or impeller 99 and the opening 86. The baffle-wall 101 is, furthermore, flanged upwardly around its peripheral margins to engage the under face of the lid 83 in order to prevent bypassing of air.

Mounted in the pan 79 and extending horizontally across the compartment a is an electric heater 102 of substantially tubular design and being provided with a plurality of colsely spaced thin annular heat-dissipating fins 103. As will be seen by reference to FIG. 6, the heater 102 and fins 103 extend vertically upwardly and downwardly across the compartment a for practically the full height thereof, the fins 103 terminating a short distance above the bottom wall 93 and just below the level of the lid 83. Also mounted in the pan 79 is a thermostatic tube 104, which effectively spans the compartment b and senses the temperature of air passing therethrough. The compartment b is finally provided with a whorl-forming wall 106 mounted encirclingly about the impeller 99, so that the impeller 99 will draw the air efficiently downwardly through the openings 15, 86, across the top of the compartment a and then upwardly and outwardly again through the openings 14, 85.

Bolted or otherwise rigidly secured to the lateral faces of the pan 79 are forwardly extending L-shaped channels 120, 121, which project forwardly beyond the pan 79 and are angulairly cut off at their forwardends for supportive engagement with an inclined instrument panel 122 located for snug-fitting closurewise disposition across the opening 9 of the base housing 1, substantially as shown in FIGS. 1 and 5. Operatively mounted on the instrument panel 122 is a conventional thermostatic control which is not specifically described herein. It is sufficient for present purposes to note that the thermostatic control is provided, on its external end, with a control knob 126. The electric heater 102 is also connected by conductors 127 to the thermostatic control in the usual and conventional manner so that the heater element 102 will go on and off intermittently responsive to temperature variations of the air passing through compartment b as sensed by the thermostatic tube 104. The oxygen control valve is connected by means of a suitable tubular conduit (not shown) to a supply-line fitting 1'29 mounted in the instrument panel 122. The oxygen control valve 95 is controlled by a dial 132 located upon the outwardly presented face of said instrument panel .122. Also mounted upon the instrument panel .122 are two small bulls-eye signal lights 134, 135, which are conventionally wired in parallel with the heater element 102 and motor 96 to afford visual evidence of the fact that these elements are electrically operative whenever such is the case during the operation of the equipment. The circuitry by which these various electrical elements are interconnected is not a part of the present invention and, therefore, is not described in detail herein, it being merely sufficient to note that the electrical circuits are connected by a conventional extension cord 136 to a suitable source of electrical energy, preferably by means of a plug-in receptacle.

When in use, the air within the infant compartment of the incubator will circulate continuously downwardly through the openings 15, 86, as previously described, and, thence, upwardly through the openings 14, 85, making a complete circuit and flowing across the top of the body of water in compartment a. for effective humidification. It should be noted in this connection that the airflows over the surface of the water in the compartment a and, at the same time, flows through the upper portions of the heat-dissipating fins 103. Consequently, the heater 102 not only serves to heat the water in compartment a and produce hurnidifying evaporation thereof, but also adds an additional increment of dry heat to the air. By adjusting the water level within the compartment a, it is possible to have a greater or laser amount of the heater 102 immersed and thereby maintain varying balances between humid heat and dry heat, so to speak. Ordinarily, this balance is not particularly critical where the premature infant is not particularly sensitive. There are, however, certain types of conditions which are encountered in premature infants where the heat-humidity balance must be very precisely maintained and this result can be effectively and conventiently obtained in the incubator A by the simple expedient of maintaining a predetermined water level With-in reasonably close limits. Inasmuch as the volume of the infant compartment in the incubator A is not particularly large and the incubator is air-tight to a substantial and practical degree, there is not too much loss of moisture. Consequently, the humidity can be maintained without an excessive amount of loss of evaporated water and the water level, once established in compartment a, does not vary too rapidly.

As will be seen by reference to FIG. 7, the tray 67 does not extend completely to the end of the recesses 10, 11, and, consequently, the air flow will travel upwardly and downwardly along the lateral side walls of the infant compartment created within the halfdomcs 16, 37, and there will be a continuous and highly desirable air circuit thus established.

As will be seen by reference to FIG. 5, the incubator A can be readily opened up to insert or remove the infant or to make major changes in the infants clothing or otherwise administer to its needs. For ordinary and'recurring situations, such as the administration of medicine or feeding, the infant can be cared for without opening the haldome ,37, but, rather, by inserting the hands through the several apertures 21, 22, 44, 45. Since the springs 62, 63, are selected to supply a counterbalancing source equivalent to approximately lbs, the weight of the tray 67, the mattress 72, and the infant, will be just about compensated for. Consequently, when the knob 56 is loosened, the tray'67 can be lifted up and down, without any danger of jarring the infant. The main electrical supply-line or extension cord 136 extends through a conventional grommet 137 set into the rear wall 2 of the base housing 1. Also rigidly mounted in the rear wall 2 of the base housing 1 are two knobs 138, 139, around which the extension cord 136 may be coiled when not in use. Finally, the side wall 3 is provided with a loop-forming flexible member 140 for holding a nebulizer bottle (not shown).

Preferably, though'not necessarily, a bracket 141 is bolted or otherwise suitably' secured in a convenient location upon the back wall of the halfdome 16 for supporting a vertical plate 142, upon which conventional wet and dry bulb thermometers 143, 144, are supported. The wet and dry bulb thermometers, obviously, are conventional and, therefore, are merely shown in dotted lines and not particularly described herein.

It should be understood that changes and modifications in the form, construction, arrangement, and combination of the several parts of the incubators for infants may be made and substituted for those herein shown and described without departing from the nature and principle of our invention.

Having thus described our invention, what we claim and desire to secure by Letters Patent is:

1. An infant incubator comprising a base housing, an infant-enclosure mounted on said housing and including a transparent stationary member having spaced side walls, a back wall, and an arcuate top wall, said member being rigidly mounted on said housing and partially enclosing the space above said housing, a transparent complementarily shaped closure rockably mounted within the stationary member at approximately the geometric center of said arcuate portion, and having a marginal portion which is disposed telescopically within and adjacent to the outer margins of the stationary member when the complementarily shaped closure member is disposed in closure-forming position, a resilient sealing element disposed around the external surfaces of the marginal portion of said complementarily-shaped closure, said sealing element having an inwardly extending resilient lip which projects laterally beyond the outer surface of the complementari-ly-shaped closure into resilient seal-forming engagement with the interiorly presented surface of the overlapping portions of the stationary member so as to form an air-lock between the stationary member and the complementarily-shaped closure when the latter is in closure-forming position, and means by which the closure can be manipulated for movement within the stationary member whereby to open and close the incubator.

2. An incubator comprising a base housing, a transparent dome-like cover mounted on said housing, said dome-like cover including a stationary shell-like halfdome rigidly mounted on said housing, said shell-like halfdome including spaced side walls and a back wall formed with an arcuate upper portion, a companion-shaped lid journaled within the side walls of said halfdome to permit pivotal movement within said halfdome, said lid having a marginal portion which projects telescopically within and is overlapped by the outer margins of the stationary halfdome, a resilient sealing element disposed around the outwardly presented surface of said marginal portion of the lid, said sealing element having an inwardly extending resilient lip which projects laterally beyond the outer surface of the companion-shaped lid into contact with the inner face of the stationary halfdome when the lid is in closure-forming position whereby to form a wiping seal between the telescopically overlapped marginal portions of the stationary halfdome and the lid, and means by which the lid can be jou'rnaled within the stationary halfdome whereby to open and close the incubator, the side and front walls of said lid, when the lid is in open position, defining a U-shaped canopy-like member which projects forwardly from said halfdome.

3. An incubator comprising a base housing, a transparent dome-like cover mounted on said housing, said dome-like cover including a stationary shell-like halfdome rigidly mounted on said housing, said shell-like halfdome including spaced side walls and a back Wall formed with an arcuate upper portion, a companionshaped lid rockably journaled within the side walls of said halfdome, said halfdome and lid each being provided with apertures having closure elements associated therewith, said lid having a marginal portion which is disposed telescopically within and adjacent to the outer margins of the stationary member when the complementarily shaped closure member is disposed in closure-forming position, a'resilient sealing element disposed around the outwardly presented surfaces of said marginal portion of the lid, said sealing element having an inwardly extending resilient lip which projects laterally beyond the outer surface of the lid into resilient wipping engagement against the inwardly presented surface of the stationary halfdome to provide an air-seal between the halfdome and the lid as the lid is moved from one position to another relative to the stationary halfdome, and means by which the lid can be rotatab-ly moved within the stationary halfdome whereby to open and close the incubator.

References Cited in the file of this patent UNITED STATES PATENTS 1,680,962 Voshardt Aug. 14, 1928 2,478,253 Doner Aug. 9, 1949 2,517,420 Gauvreau Aug. 1, 1950 2,600,240 Grieb June 10, 1952 2,617,702 Manning Nov. 11, 1952 

